GelSight senses surfaces in 3D with rubber and paint

Researchers from MIT have created a handheld device called GelSight that provides
ultra-high resolution 3D scans of microscopic surface
structure.

The main section of the system is a small slab of transparent,
synthetic rubber that's coated on one side with a paint containing
tiny flecks of metal. If you push the rubber against an object, the
paint-coated side morphs to closely conform to the object's
texture.

In the video, we see a guy squidge his finger into the rubber,
instantly amplifying the microscopic structure of his skin, and
revealing a bold indentation of his fingerprint
on the other side.

Once this rubbery solution is connected to a series of lights
and cameras, it can be used to create 3D models of the underlying
structure. The models can register physical features less than a
micrometer in depth and about two micrometers across -- enough to
capture the raised ink patterns on a $20 bill.

GelSight grew out of a project to create tactile
sensors for robots. But MIT researchers Edward Adelson and
Micah Kimo Johnson quickly realised that their system provided much
higher resolution than robotic sensing required.

The scanner has plenty of real-world applications. The team is
already in discussion with aerospace companies and equipment
manufacturers who are interested in using GelSight to check the
microscopic integrity of their products. It could have applications
in medicine, forensics, ballistics and biometrics.